182 GERM-CELL CYCLE IN ANIMALS 
Buchner (1910a, 19106) had no difficulty in find- 
ing the ‘‘besondere Korper” of Elpatiewsky and in 
tracing it during the cleavage stages. He claims that 
it originates from the “accessory fertilization cell” 
described by Stevens (1904) as degenerating after 
the egg breaks away from the oviduct wall, and that 
it is chromidial in nature and should therefore be 
called ‘‘Keimbahnchromidien.” Stevens (1910), 
however, has carefully examined abundant material 
from Sagitta elegans and S. bipunctata, and no connec- 
tion between the “accessory fertilization cell”? and 
the “‘besondere Kérper”’ could be traced, the latter 
appearing for the first time at the stage when the 
egg and sperm nuclei lie side by side in the middle 
of the egg, thus confirming Elpatiewsky’s conclusions. 
She admits the possibility of the origin of the “be- 
sondere Kérper” from granules of the accessory 
fertilization cell, provided this material loses its stain- 
ing capacity for a period, and suggests also that the 
granules of chromatin-like material extruded from 
the nucleus of the egg during maturation may take 
part in its formation. Miss Stevens also believes 
with Elpatiewsky that the “‘besondere Kérper”’ 
divides unequally between the two daughter cells of 
the primordial germ cell and that this is a differential 
division. She was unable, however, to detect any 
constant difference between either the cytoplasm or 
the nuclei of odgonia and spermatogonia. It is 
worthy of mention that Elpatiewsky (1910) believes 
that the “‘besondere Koérper” may orviginate “aus 
dem achromatischen Kernkorper.”’ 
